Cyclone Yasi is 500km wide and bearing down on the state of Queensland, which has already suffered from devastating floods.
The state premier, Anna Bligh, has described it as a "monster, killer storm" and she predicted deadly surges inland.
It is likely to cross the coast sometime late on Wednesday local time - and could hit anywhere along a 400-mile stretch between Cairns and Bowen.
It already is a Category 3 cyclone, and is likely to intensify to a Category 4, with gusts of wind expected to reach 160mph.
Airlines are laying on extra flights to get people out of the area, especially tourists with nowhere else to go.
But the storm is so wide that finding somewhere safe to move to will be difficult for tens of thousands of people.
The holiday resort of Hamilton Island has already been evacuated, and coal terminals in Bowen and Mackay have closed down in another blow to the state's mining industry which has already been disrupted by flooding.
Around 350,000 people live in the region, and they are being urged to make preparations on Tuesday because heavy rain and winds could begin to intensify while the eye of the storm is still a long way north.
Ms Bligh said the threat to life and property was compounded by the possibility it could trigger a tsunami-like storm surge, especially if its landfall coincided with a high tide.

Queensland Premier Anna Bligh said the situation and exact impact of the cyclone would become clearer this afternoon.

---------- Post added 2011-02-01 at 07:46 PM ----------

*MAJOR UPDATE*

The cyclone has reached the highest level of storm categorisation.

6.03am The Bureau of Meteorology has upgraded Yasi to a Category 5 cyclone. The highest level of storm categorisation, this will bring winds above 280km/h and certain destruction, particularly within the warning areas from Port Douglas to Townsville. The Bureau warns the impact of the storm is "likely to be more life threatening than any experienced during recent generations".

Holy shi... This seems to be serious! Lucky for me, I live in the calm Sweden, nothing ever happens here

This.

It's nice to live in the most passive country ever. Both weather and war wise.
I hope the Aussies can handle the storm and that they don't have too many casualties.
If there is a god, may he have mercy on their poor souls.

Originally Posted by Urti

Seriously this. I'm a high-speed, low-drag, supah-healah. Doling out the feel-goods LIKE A BAWS, keeping everyone shiny, happy and cool. Staying on top of my game, even in a combat situati....THERE'S THAT DAMN GROUNDHOG AGAIN!!!

It's not a joke, regardless not going to turn this into a 2012 end of the world discussion.

Rumors are the storm is slowing down, which is bad ironically, it means the storm will build even more pressure then expected before hitting land. Supposed to be hitting Australia within the hour. Roof tops/trees etc have already started falling.